Provide a man-page describing the usage of U-Boot on the Milk-V Mars CM and Milk-V Mars CM Lite boards.
Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com Reviewed-by: E Shattow lucent@gmail.com --- v4: remove .rst extension from toctree links remove superfluous word 'connected' describing booting from SPI flash v3: correct device-tree names suggest not to use mac initialize refer to XMODEM-1K v2: refer to tio as tool for booting via UART describe how to update serial number description updates as suggested by E. Shattow --- doc/board/starfive/index.rst | 1 + doc/board/starfive/milk-v_mars_cm.rst | 193 ++++++++++++++++++++++++++ 2 files changed, 194 insertions(+) create mode 100644 doc/board/starfive/milk-v_mars_cm.rst
diff --git a/doc/board/starfive/index.rst b/doc/board/starfive/index.rst index 2762bf74c11..afa85ad2540 100644 --- a/doc/board/starfive/index.rst +++ b/doc/board/starfive/index.rst @@ -7,5 +7,6 @@ StarFive .. toctree:: :maxdepth: 1
- milk-v_mars.rst + milk-v_mars + milk-v_mars_cm visionfive2 diff --git a/doc/board/starfive/milk-v_mars_cm.rst b/doc/board/starfive/milk-v_mars_cm.rst new file mode 100644 index 00000000000..68561adadfc --- /dev/null +++ b/doc/board/starfive/milk-v_mars_cm.rst @@ -0,0 +1,193 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +Milk-V Mars CM +============== + +U-Boot for the Milk-V Mars CM uses the same U-Boot binaries as the VisionFive 2 +board. In U-Boot SPL the actual board is detected and the device-tree patched +accordingly. + +The Milk-V Mars CM Lite comes without eMMC and needs a different pin muxing +than the Milk-V Mars CM. The availability and size of the eMMC shows up in the +serial number displayed by the *mac* command, e.g. +MARC-V10-2340-D002E016-00000304. The number after the E is the MMC size. U-Boot +takes a value of E000 as an indicator for the Lite version. Unfortunately the +vendor has not set this value correctly on some Lite boards. + +Please, use CONFIG_STARFIVE_NO_EMMC=y if EEPROM data indicates eMMC is present +on the Milk-V Mars CM Lite. Otherwise you will not be able to read from the +SD-card. + +The serial number can be corrected using the *mac* command: + +.. code-block:: + + mac read_eeprom + mac product_id MARC-V10-2340-D002E000-00000304 + mac write_eeprom + +.. note:: + + The *mac initialize* command overwrites the vendor string and the MAC + addresses. This is why it is avoided here. + +By default the EEPROM is write protected. The write protection may be overcome +by connecting the "GND" and "EN" test pads on top of the module. + +Building +~~~~~~~~ + +1. Add the RISC-V toolchain to your PATH. +2. Setup ARCH & cross compilation environment variable: + +.. code-block:: none + + export CROSS_COMPILE=<riscv64 toolchain prefix> + +The M-mode software OpenSBI provides the supervisor binary interface (SBI) and +is responsible for the switch to S-Mode. It is a prerequisite to build U-Boot. +Support for the JH7110 was introduced in OpenSBI 1.2. It is recommended to use +a current release. + +.. code-block:: console + + git clone https://github.com/riscv/opensbi.git + cd opensbi + make PLATFORM=generic FW_TEXT_START=0x40000000 + +(*FW_TEXT_START* is not needed anymore after OpenSBI patch d4d2582eef7a +"firmware: remove FW_TEXT_START" which should appear in OpenSBI 1.5.) + +Now build the U-Boot SPL and U-Boot proper. + +.. code-block:: console + + cd <U-Boot-dir> + make starfive_visionfive2_defconfig + make OPENSBI=$(opensbi_dir)/build/platform/generic/firmware/fw_dynamic.bin + +This will generate the U-Boot SPL image (spl/u-boot-spl.bin.normal.out) as well +as the FIT image (u-boot.itb) with OpenSBI and U-Boot. + +Device-tree selection +~~~~~~~~~~~~~~~~~~~~~ + +Depending on the board version U-Boot sets variable $fdtfile to either +starfive/jh7110-milkv-mars-cm.dtb (with eMMC storage) or +starfive/jh7110-milkv-mars-cm-lite.dtb (without eMMC storage). + +To overrule this selection the variable can be set manually and saved in the +environment + +:: + + env set fdtfile my_device-tree.dtb + env save + +or the configuration variable CONFIG_DEFAULT_FDT_FILE can be used to set to +provide a default value. + +The variable *$fdtfile* is used in the boot process to automatically load +a device-tree provided by the operating system. For details of the boot +process refer to the :doc:`U-Boot Standard Boot <../../../develop/bootstd>` +description. + +Boot source selection +~~~~~~~~~~~~~~~~~~~~~ + +The low speed connector nRPIBOOT line is used to switch the boot source. + +* If nRPIBOOT is connected to ground, the board boots from UART. +* If nRPIBOOT is not connected, the board boots from SPI flash. + +Compute module boards typically have a switch or jumper for this line. + +Flashing a new U-Boot version +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +U-Boot SPL is provided as file spl/u-boot-spl.bin.normal.out. Main U-Boot is +in file u-boot.itb. + +Assuming your new U-Boot version is on partition 1 of an SD-card you could +install it to the SPI flash with: + +:: + + sf probe + load mmc 0:1 $kernel_addr_r u-boot-spl.bin.normal.out + sf update $kernel_addr_r 0 $filesize + load mmc 0:1 $kernel_addr_r u-boot.itb + sf update $kernel_addr_r 0x100000 $filesize + +For loading the files from a TFTP server refer to the dhcp and tftpboot +commands. + +After updating U-Boot you may want to reboot and reset the environment to the +default. + +:: + + env default -f -a + env save + +Booting from UART +~~~~~~~~~~~~~~~~~ + +For booting via UART U-Boot must be built with CONFIG_SPL_YMODEM_SUPPORT=y. + +With nRPIBOOT connected to ground for UART boot, power the board and upload +u-boot-spl.bin.normal.out via XMODEM. Then upload u-boot.itb via YMODEM. + +The XMODEM implementation in the boot ROM is not fully specification compliant. +It sends too many NAKs in a row. Tio is a terminal emulation that tolerates +these faults. + +:: + + $ tio -b 115200 --databits 8 --flow none --stopbits 1 /dev/ttyUSB0 + [08:14:54.700] tio v2.7 + [08:14:54.700] Press ctrl-t q to quit + [08:14:54.701] Connected + + (C)StarFive + CCC + (C)StarFive + CCCCCCCC + +Press *ctrl-t x* to initiate XMODEM-1K transfer. + +:: + + [08:15:14.778] Send file with XMODEM + [08:15:22.459] Sending file 'u-boot-spl.bin.normal.out' + [08:15:22.459] Press any key to abort transfer + ........................................................................ + .......................................................................| + [08:15:22.459] Done + + U-Boot SPL 2024.07-rc1-00075-gd6a4ab20097 (Apr 25 2024 - 16:32:10 +0200) + DDR version: dc2e84f0. + Trying to boot from UART + CC + +Press *ctrl-t y* to initiate YMODEM transfer. + +:: + + [08:15:50.331] Send file with YMODEM + [08:15:53.540] Sending file 'u-boot.itb' + [08:15:53.540] Press any key to abort transfer + ........................................................................ + … + ...............| + [08:15:53.540] Done + Loaded 1040599 bytes + + + U-Boot 2024.07-rc1-00075-gd6a4ab20097 (Apr 25 2024 - 16:32:10 +0200) + +Booting from SPI flash +~~~~~~~~~~~~~~~~~~~~~~ + +With nRPIBOOT disconnected from ground for SPI boot, power up the board. You +should see the U-Boot prompt on the serial console.